Boring-drill.



-No. 645,2!9. Patented Mar. '13, I900. c. s. STAFFORD.

BORING DRILL.

(Application filed July 1, 1899.)

(No Model.)

wi bnelo ow,

0.. WASHI'IGTON u c UNITED STATES PATENT OFFICE;

CHARLES S. STAFFORD, OF SAN FRANCISCO, CALIFORNIA.

BORING-DRILL.

SPECIFICATION forming part of Letters Patent No. 645,219, dated March 13, 1906. Application filed my 1,1899. Serialll'o. 722,553. (No model.)

To coZZ whom it may concern.-

Be it known that 1, CHARLES S. STAFFORD, a citizen of the United States,residin gin the city and county of San Francisco, State of California, have invented an Improvement in Boring- Drills; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to boring and drilling devices. I

It consists in the parts and the constructions and combinations of parts hereinafter described and claimed.

Figure 1 is a View of the drill. Fig. 2 is a vertical section of the same. Fig. 3 is a horizontal section on line y y of Fig. 2. Fig. 4 is a bottom view of the upper pinion. Fig. 5 is a view of the upper part of the sleeve. Fig.

. 6 is a vertical section of the same-at right angles to Fig. 2. Fig. 7 is abottom view of the sleeve. Fig. 8 is a top view of the lower pinion.

A is a stock which may be made of any suitable form. I have here shown it with the upper end made cylindrical or tubular in shape, having abreast-piece B and a supporting-handle C, by which it can be held with one hand while the other operates the crank D, which is fixed so as to turn the beveled driving-gear E. This gear-wheel has the exterior toothed part E and the inner toothed portion E The spindle F is screw-threaded and is supported and turnable in the stock A, its upper end extended'into the tubular upper portion when it is retracted and having sufficient length to allow it to be advanced as much as may be desired. Upon this spindleis loosely mounted the sleeve F, having a longitudinal slit on one side, and its central portion is threaded on the outside, as shown. Upon the ends of this sleeve are mounted two beveled pinions G and G, the outer one engaging the outer teeth F. of the bevel-wheel and the inner one engagingtheinnerteeth E These pinions are loosely turnable upon the sleeve, and between them is mounted a longitudinally-slidable two-part collar H, having in the interior a feather I, which, passing through the slit in the sleeve, engages with a keyway f in the spindle, so that the two-part collar and the sleeve are always turnable with the spindle.

I The pinions G G have upon them projecting toward the collar lugs 71, and the-collar has corresponding grooves or sockets formed in its ends, so that when the collar is advanced in one direction itwill engage the lug 'i'upon one of the pinions and be disengaged from the other, and when advanced 'in the opposite direction it will in the same manner be disengaged from the first pinion and engaged with the other. By this movement of the collar the speed of rotation of the drill may be changed and will depend upon whether the interior or exterior gear is doing the driving.

When boring with a small boring-tool, the exterior gear may be made to drive and produce a higher rate of speed; but if a larger boring-tool is being used the interior gear may .be made to do the driving, and the rate of rotation will be slower.

In order to move the two-part collar H along the sleeve, a milled disk .I is interposed between the two parts of the collar, and the'inner portion is threaded, so that it turns upon the threaded portion of the sleeve. The two parts of the collar are united to move in unison by turning up or forming lugs upon the endof the feather I, which thus engage with the two parts of the collar and hold it so that it moves practically as one piece. It will be seen that by turning the disk J in one direction it will be advanced along the sleeve, so that when the lug t' of the disengaged pinion is in line with the corresponding slot h in the adjacent end of the collar the latter may be moved so that its slot will engage with the lug of that pinion, while at the same time the slot at the opposite end of the collar will be disengaged therefrom,thus changing the driving from one gear to the other.

To the lower end of the spindle is fixed the chuck K, of any suitable or desired character, which will hold the boring tool or drill in line with the spindle. V.

L is a sleeve which forms the lower part of the stock A, and within this sleeve is loosely fitted an interiorlythreaded collar 0. The inner end of this collar is grooved or channeled upon the outside, as shown at O, and a screw or pin P, passing through the sleeve, engages with this groove, so that the collar may rotate without advancing. Within the inner face of which has the same curvature as the exterior of the collar, and by means of a screw R, having a milled head, this brakepiece may be forced against the collar, so as to lock it and prevent its turning. In this condition when the drill-spindle F is turned it will advance through the collar by means of the engaging screw-threads and will thus feed forward at a rate dependent upon the pitch of the screw-threads. When the brakeshoe Q is tightened against the collar 0, the drill-spindle .will feed, but only when the sleeve L is held against independent rotation.

If it is desired to stop the feed, the screw R is loosened and the pressure upon the brakeshoe Q. relieved. This allows the collar to turn freely within the sleeve, being guided by the annular groove and pin previously described; but it does not advance the spindle, since its frictional pressure upon the screw is sufficient to cause it to turn with the screw and produce no advance or feed of the boringtool. Whenever it is desired to feed again by tightening the brake, the collar will be stopped, and the screw will then advance within it as much as may be desired.

The flange of the collar 0 has a raceway to receive balls 1;,whioh travel against the flange of the sleeve and reduce friction when there is no feed, thus allowing the collar to turn easily. By a set-screw r the collar may be fixed to the spindle when no feed is desired.

In order to hold the work against the pressure of the boring-tool, the yoke S is fitted and loosely turnable upon the sleeve L, and the projecting ends of the yoke are fitted in any suitable or desired manner to receive a flexible chain T, one end of which being connected with one end of the yoke the bight of the chain is passed around the part to be bored or drilled and the other end is connected with the opposite side of the yoke, thus holding the work, so that when the drill is advanced it does not push the work away.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is v 1. In a boring-tool,a stock,a screw-threaded spindle loosely turnable within the stock,with means for securing the boring-tool in line therewith, a sleeve loosely mounted. on said spindle having a longitudinal slit and its central outer portion threaded, a beveled gear journaled and turnable upon the side of the stock having outer and inner teeth, corresponding beveled pinions loosely turnable upon the ends of the sleeve, having lugs upon their adjacent faces, a two-part sliding collar loosely fitting the sleeve between the pinions, having slots in its outer ends adapted to engage either of the lugs upon the pinions, a feather movable in a keyway in the spindle and means for advancing the two-part sliding collar in either direction to engage with one of the pinions and disengage it from the other. 7

2. In a boring-tool, astock, a threaded drillspindle turnable therein, a sleeve loosely mounted on the spindle having a longitudinal slit and its central portion threaded, a gear-wheel journaled and turnable upon the stock having outer and inner rows of teeth, pinions loosely turnable upon the ends of the sleeve and engaging the outer and inner teeth of the wheel, a two-part sliding collar interposed between the pinions having a length less than the distancebetween the pinions, a milleddisk turnable with relation to the collar, having the interior screw-threaded and fitting corresponding threads upon the central part of the sleeve,lugs projecting from the adjacent faces of the pinions, corresponding slots in the outer ends of thetwo-part collar, so that one pinion will be engaged and the other disengaged by the advance of the-collar along the spindle.

3. In a boring-tool, a stock, a, drill-spindle turnable therein, asleeve mounted on the spindle, a driving-gear journaled and turnable upon the stock, and having outer and inner rows of teeth, pinions turnable upon the sleeve, the teeth of one engaging the outer and the other the inner teeth of the gear, a

two-part collar loosely fitting the sleeve between the pinions having slots in the ends adapted to engage corresponding lugs upon the inner faces of the pinions,a key or feather slidable ina key way in the spindle having its ends upturned to engage the two parts of the collar and unite them so that they become one and move in unison, a disk turnable upon the sleeve between the inner ends of the twopart collar having screw-threads fitting corresponding threads on the sleeve whereby the collar may be advanced to engage either of the pinions and be disengaged from the other.

4. In a boring-tool, the combination of a stock, a drill-spindle turnable therein and mechanism by whichit is rotated, a sleeve forming the lower end of the stock and an internally-threaded collar loosely turnable within the sleeve, having its inner end formed with an exterior annular groove and its lower end provided with an antifriction-bearing for the sleeve, a screw or pin passing throughthe inner end of the sleeve and engaging the annular groove in the collar, to prevent end movement of said collar, a brake-piece loosely seated in the sleeve and a screw for operating the same, a yoke loosely seated on the outer end of the sleeve below the said brakescrew and a means carried by the yoke for engaging the work to be drilled.

In witness whereof I have-hereunto set my hand.

CHARLES S. STAFFORD. \Vitnesses:

S. H. Nounsn, GEO. H. STRONG. 

